RESUMEN
We describe a rare case of nontraumatic normal pressure cerebrospinal fluid rhinorrhea. A 33-year-old male was admitted to our hospital due to continuous rhinorrhea but without a history of specific trauma. We performed various radiological evaluations, and on bone-window CT, detected severe bilateral extension of the sphenoid sinus into the greater wing. MRI and CT cisternography revealed that contrast media and cerebrospinal fluid had leaked from the middle cranial fossa to the sphenoid sinus. Transethmoidal sphenoid approach and sphenoid sinus fat obliteration was successfully performed by an otolaryngologist. On postoperative day 2, however, the patient's mental condition deteriorated and CT showed the development of acute obstructive hydrocephalus. Ventriculo-peritoneal shunt was then successfully performed and the patient was discharged. Nontraumatic normal pressure cerebrospinal fluid rhinorrhea involving leakage through the middle cranial fossa is very rare, this report discussed the etiological, anatomical and surgical considerations of this case.